Hypnosis measured with monitors of anesthetic depth - EEG changes during the test for Harvard Group Scale of Hypnotic Susceptibility

Introduction

Hypnotic trance can be defined as a non-ordinary state of consciousness that is accompanied by a number of neurophysiological changes, including brain electrophysiology. In addition to subjective measures, corresponding objective parameters are needed in experimental and clinical hypnosis research but are complex, impractical, or unspecific. A similar challenge exists for the measurement and monitoring of drug-induced hypnosis, namely general anesthesia. The observation of changes in EEG induced by narcotics has led to the development of monitors for the depth of anesthesia based on EEG parameters. We investigated whether two such monitors react to the induction and maintenance of hypnosis during a highly standardized procedure.

Methods

A total of 56 volunteers were monitored for the bispectral index (BIS) and cerebral state index (CSI) (range 0-100, >95 considered "awake") during the Harvard Group Scale of Hypnotic Susceptibility test. For this test, trance is induced by a taped text and followed by 12 tasks performed under hypnosis. In contrast to random forms of hypnosis, this represents a standardized, worldwide-established condition. According to the resulting score, participants were classified into suggestibility groups in order to evaluate whether the electrophysiological measurements of BIS and CIS indices differ between high and low suggestible persons. Furthermore, participants were asked to rate their hypnotic depth (HD, 1-10) at every task of the test.

Results

Scores dropped significantly from a mean of 97.7 to 86.4 for BIS and from 94.6 to 77.7 for CSI with the induction of hypnosis to stay throughout hypnosis at levels of approximately 88.6 or 82.9, respectively. Results did not differ between high- and low-suggestible participants. The means of the subjective score of hypnotic depth and of the electrophysiological measurements showed a similar course. However, no correlation was found between BIS or CSI values and scores of hypnotic depths.

Conclusion

Monitors for depth of anesthesia respond to changes in consciousness, including trance states of hypnosis. However, specificity is unclear. Practically, in hypnosis research with the exclusion of drug effects or sleep, these monitors might be helpful to test and compare the efficacy of induction texts and to detect disturbances of trance state.

Hypnotic and direct suggestions affect attitudes toward seeking professional psychological help

This study investigated the impact of hypnotic suggestions on improving attitudes toward seeking professional psychological help (ATSPPH). The study administered the Chinese version of the ATSPPH scale on 303 college students, of which 61 with low levels of ATSPPH were recruited as the participants (male: 18; female: 43). All participants were tested with the Harvard Group Scale of Hypnotic Susceptibility, Form A, prior to the formal experiment and assigned with balancing hypnotic susceptibility in hypnotic suggestion, relaxation, or control groups. The main results were as follows: (1) counter-attitudinal information significantly improved explicit ATSPPH only for the hypnotic suggestion and relaxation groups, (2) the hypnotic suggestion group exhibited improvement in implicit ATSPPH and (3) a difference was observed between explicit and implicit attitudes in the process of providing counter-attitudinal information when changing ATSPPH.

Hypnotic analgesia in chronic pain: role of psychopathology and alexithymia

Although the belief that hypnotizability is a mental dysfunction has been refuted over time, there is still research today that seeks to explore and clarify this preconception. The results of recent research indicate that, on the contrary, greater psychopathology is more frequent in subjects with low hypnotic susceptibility. Using the Stanford Hypnotic Susceptibility Scale type A (SHSS-A) for hypnotizability, Symptom Checklist-Revised (SCL-90-R) for psychopathology, and the Somatosensory Amplification Scale (SSAS) and Toronto Alexithymia Scale (TAS-20) for psychosomatic dimensions, we found no relationship between baseline psychopathology, alexithymia and hypnotizability in 69 subjects with chronic pain in this retrospective observational study. Psychopathology did not affect the 2-month outcomes of hypnotic suggestions for pain in terms of either pain (assess using Italian Pain Questionnaire), anxiety or depression (assessed through Hospital Anxiety and Depression Scale) scores. Furthermore, i) no relationships were found between hypnotizability and degree of either psychopathology or alexithymia, definitively eliminating any doubts about the belief that hypnosis is a mental dysfunction; ii) only single hypnotic phenomena (SHSS-A) could be linked to some psychopathological dimensions; iii) analgesia suggestions also acted on anxiety and depression; and iv) the use of hypnotic suggestions for analgesia revealed a close relationship between improvements in sensorial and evaluative dimensions of pain and mitigation of anxiety. Hypnosis thereby seems to be a powerful tool in psychosomatic medicine whose effects on mind and body are inextricably linked.

Studies in patients with temporomandibular disorders pain: Can scales of hypnotic susceptibility predict the outcome on pain relief?

Many medical conditions are claimed to benefit when hypnosis is incorporated into their treatment. For some conditions, the claims are largely anecdotal, but the treatment of pain stands out in two ways. First, there is a strong body of evidence that hypnosis can produce clinically useful analgesic effects. Second, since innocuous pain can be induced in the laboratory, the process can be explored rigorously. This idea assumes that experimentally induced pain and clinical pain behave identically. We describe using experimentally induced pain in patients already suffering from temporomandibular disorders. Scanning results indicate that the pain and its amelioration are the same in the two circumstances. Moreover, the absence of any impact upon a nociceptive trigemino-facial reflex implies that the impact of hypnosis is purely cortical. Finally, we address the observation that clinical success correlates poorly with hypnotic susceptibility scores. It is proposed that a painful experimental situation induces anxiety. This, like hypnosis, has been associated with an emphasis on right hemisphere activity. Thus, clinical anxiety may render a person more responsive to hypnosis than would be indicated by a susceptibility test delivered in stress-free circumstances.

In medio stat virtus: The importance of studying mediums in hypnosis research

Most of the experimental investigations on hypnosis used to compare small samples of individuals with low or high responsiveness to hypnosis by systematically excluding medium responders. The present article underlines the limitations of this methodological approach that may have partially weakened the scientific impact of hypnosis research. In fact, the mediums-neglecting bias might be one of the reasons why some investigations suffer from low replicability and generalizability. Themes such as hypnotizability scales, suggestibility, statistical power, and research design are critically reviewed with the aim of proposing a more rigorous approach that boost up impact and reliability of hypnosis research. In particular, the recruitment of medium hypnotizables and the adoption of a within-instead of a between-subjects design currently seem to be some of the best recommendations for strengthening hypnosis research, as well as to renew the dialogue between clinical and experimental hypnosis.

Hypnotizability and psychopathology of patients with personality disorders

Assessment of hypnotizability is useful in research and predicting the effects of hypnosis in clinical practice. There are few contemporary scientific reports examining the relationship between hypnotizability and psychopathological personality dimensions. The current study explores the connections between abnormal personality in psychiatric patients and the hypnotizability level. Fifty-five patients with anxiety and personality disorders who previously completed the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) were invited to undergo the Elkins Hypnotizability Scale - Clinical Form (EHS-CF). The hypnotizability scores comprise a normal distribution but shifted toward low scores. Twenty-seven patients were included in the low hypnotizability (LOW) group, and 28 patients in the medium to high (MID-HIGH) group. The number of participants with high scores on the Psychopathic Deviate and Paranoia MMPI-2 clinical scales was significantly higher in the LOW than in the MID-HIGH group. Patterns of associations between hypnotizability and psychopathology differed in the two groups. The results indicate that moderate hypnotizability should be considered a normal trait that has no meaningful relationship with psychopathology, but certain dysfunctional symptoms of personality disorders may entail resistance and a defensive attitude toward the hypnotherapy, resulting in a tendency to obtain lower hypnotizability.

Hypnotherapy for persons with Irritable Bowel Syndrome: A three-arm randomized controlled trial

The current study sought to (1) compare the efficacies of Ericksonian hypnotherapy, traditional hypnotherapy, and educational talk in treating irritable bowel syndrome (IBS), and to (2) evaluate the impacts of hypnotic susceptibility on participants' responses to hypnotherapy. The study adopted a three-arm randomized controlled trial design and achieved an effective sample size of 144. Self-reported psychological questionnaires were used to assess participants' IBS symptom severity, health-related quality of life, and coping patterns at baseline, immediately post-intervention, and 3 months after intervention. The evaluation focused primarily on IBS symptom severity and health-related quality of life, as well as on the illness coping patterns of symptom catastrophizing and symptoms-related social hypervigilance.The findings showed that significant improvements in IBS symptom severity occurred in all three types of study groups immediately after completion of the intervention (p < .05, η_ρ² = .20). However, only the traditional hypnotherapy groups and the Ericksonian hypnotherapy groups still had a notably significant decrease in symptoms 3 months after the intervention, whereas the educational talk groups had dropped back to pre-treatment symptom levels at the 3-month follow-up. The amplitude of change of symptom catastrophizing in the traditional hypnotherapy groups was stronger than that in the Ericksonian hypnotherapy groups after completion of the intervention, and the two types of hypnotherapy groups were significantly lower in symptom catastrophizing both immediately after the intervention and also 3 months post-intervention (p < .001, η_ρ² = .17). The other coping mechanism studied, symptoms-related social hypervigilance, showed a significant decline only in the Ericksonian hypnotherapy groups (ps < .001, η_ρ² = .45). Interestingly, in the traditional hypnotherapy groups, persons with higher hypnotic susceptibility showed significant improvement in symptom severity, health-related quality of life, and coping patterns following treatment. Notably, the effects from Ericksonian hypnotherapy for IBS diverged from the effects from traditional hypnotherapy. Finally, both Ericksonian hypnotherapy and traditional hypnotherapy appeared to have greater positive effects than educational talk did, but at different levels.

Placebo and hypnosis in the clinical setting: Contextual factors in hypnotic analgesia

The assumption that hypnotic analgesia produces placebo effects is controversial. The cognitive dimension that can distinguish hypnosis from placebo analgesia has been suggested as hypnotic susceptibility. The aim of this study is to investigate the role of the relationship between patient and therapist, assumed to produce the placebo effect, in the clinical context of hypnotic treatment for pain. Seventy subjects were given hypnosis administered by the therapist in person (Group A) and 37 practiced self-hypnosis (Group B) for 8 weeks. The Somatosensory Amplification Scale (SSAS), Stanford hypnotic susceptibility scale type A, Cold pressor test (CPT) and SCL-90 were administered at baseline, and Italian Pain Questionnaire (IPQ) dimensions were used as outcome measures. The SSAS did appear to reflect the efficacy of hypnotic analgesia in all pain variables explored, but only in Group B. An improvement in pain intensity and all IPQ dimensions were found at 8 weeks. In particular, an improvement in the affective dimension of pain, with a medium-high effect size (η2 = .774), was recorded after hypnotic analgesia, with the outcome being better in Group A than in Group B (p = .001). This outcome was independent of hypnotic susceptibility in both groups. Considering our hypothesis that, given the administration of the same suggestions, the therapist could promote the placebo response, contributing to the improvement in the affective dimension of pain outcome, which exhibited a response to the hypnotic treatment independently of hypnotic susceptibility.

Heartbeat-Evoked Cortical Potential during Sleep and Interoceptive Sensitivity: A Matter of Hypnotizability

Individuals with different hypnotizability display different interoceptive sensitivity/awareness (IS) and accuracy (IA), likely sustained by morphofunctional differences in interoception-related brain regions and, thus, possibly also observable during sleep. We investigated the heartbeat-evoked cortical potential amplitude (HEP) during sleep, its association with IS, and the role of hypnotizability in such association. We performed a retrospective analysis of polysomnographic recordings of 39 healthy volunteers. Participants completed the Multidimensional Assessment of Interoceptive Awareness (MAIA), measuring IS and IA, and underwent hypnotic assessment via the Stanford Hypnotic Susceptibility Scale, form A. The amplitude of the early and late HEP components was computed at EEG frontal and central sites. In both regions, the early HEP component was larger in N3 than in N2 and REM, with no difference between N2 and REM. Greater HEP amplitude at frontal than at central sites was found for the late HEP component. HEP amplitudes were not influenced by the autonomic state assessed by heart rate variability in the frequency and time domains. We report for the first time a positive correlation between the central late HEP component and MAIA dimensions, which became non-significant after removing the effects of hypnotizability. Our findings indicate that hypnotizability sustains the correlation between IS and HEP amplitude during sleep.

An evolutionary approach to hypnotizability

We propose here an evolutionary interpretation of the presence of highly hypnotizable persons (highs) among the general population. Current experimental evidence suggests the presence of stronger functional equivalence between imagery and perception, non-opioid cognitive control of pain, favorable cardiovascular asset, and greater interoceptive sensitivity in highs. We hypothesize that these characteristics were greatly relevant to our ancestors' survival, and that they may have facilitated the natural selection of individuals who are now named "highs" due to one of their side effects - the proneness to accept suggestions - as part of the reported physiological features. Unfortunately, our theoretical hypothesis cannot be currently experimentally proven. We believe, however, that looking at hypnotizability in a naturalistic, evolutionary perspective may emphasize the importance of its physiological correlates in daily life and in the prediction of the outcome of medical treatments.

Multisensory Integration Is Modulated by Hypnotizability

This study investigated multisensory integration in 29 medium-to-high (mid-highs) and 24 low-to-medium (mid-lows) hypnotizable individuals, classified according to the Stanford Hypnotic Susceptibility Scale, Form A. Participants completed a simultaneity judgment (SJ) task, where an auditory and a visual stimulus were presented in close proximity to their body in a range of 11 stimulus onset asynchronies. Results show that mid-highs were prone to judge audiovisual stimuli as simultaneous over a wider range of time intervals between sensory stimuli, as expressed by a broader temporal binding window, when the visual stimulus precedes the auditory one. No significant difference was observed for response times. Findings indicate a role of hypnotizability in multisensory integration likely due to the highs' cerebellar peculiarities and/or sensory modality preference.

The relationship between expectation and hypnotic susceptibility: a literature review

Researchers do not completely understand how hypnosis functions or what variables can predict an individual to have a high or low hypnotic susceptibility. Expectation is a variable that has been studied, but researchers disagree on the effect it has on hypnotic susceptibility. The purpose of this paper is to obtain a comprehensive understanding of how personal expectations affect hypnotic susceptibility. To this end, a critical literature review was conducted on studies dating from 1964 to 2017 examining the relationship between expectation and hypnotic susceptibility of college students. To be included in this review, all studies were required to measure both the participants' expectations of being hypnotized and their hypnotizability with a hypnotic susceptibility scale. An exhaustive search of the PsycINFO database identified 19 studies satisfying the listed and other requirements. Results indicated that expectancies of being hypnotized and hypnotic susceptibility have a very small correlation. Expectations assessed after the induction procedure tended to obtain higher correlations with hypnotic susceptibility than expectations assessed before the induction. Additionally, studies that assessed expectation by providing participants with a detailed written description of each suggestion tended to obtain higher correlations with hypnotic susceptibility than studies that did not give participants any information about the suggestions. When all is considered, expectation does not appear to be highly correlated with hypnotic susceptibility; however the modest correlation observed remains worthy of study as it is higher than other tested variables.

Hypnotisability-related interoceptive awareness and inhibitory/activating emotional traits

Emotions are influenced by several individual factors. Hypnotizability - a psychophysiological trait associated with morpho-functional cerebral and cerebellar variations able to sustain differences in interoception and emotion - could be one of them. The aims of the study were to find out possible differences in Interoceptive Awareness (IA) and in the emotional traits sustained by the Behavioral Inhibition/Activation System (BIS/BAS) in participants with high (highs), medium (mediums) and low (lows) hypnotizability and to investigate the association of interoceptive awareness and BIS/BAS related emotional traits as a function of hypnotizability. Thus, IA and BIS/BAS were studied in 284 subjects of both genders by the Multidimensional Assessment of Interoceptive Awareness (MAIA) and by BIS/BAS scales, respectively. Significantly lower BIS scores (lower inhibitory control/conflict monitoring) in highs and lows with respect to mediums and significantly higher IA (proneness to notice and interpret interoceptive information) in highs with respect to mediums and lows were found. In addition, different correlations between MAIA and BIS/BAS scales were observed in the three groups, indicating different hypnotizability-related associations.The hypnotizability-related relation between interoceptive awareness and emotional traits could be accounted for by different models and their knowledge may be relevant to the science of emotion and to clinical applications.

Relationship between hypnosis and personality trait in participants with high or low hypnotic susceptibility

BACKGROUND

The relationship between normal personality and hypnotic susceptibility is important for understanding mental processing and mental disorders, but it is less consistent in normal people or in patients with a psychiatric disorder. We have hypothesized that the correlation exists but varies in individuals with different levels of hypnotizability.

PARTICIPANTS AND METHODS

We invited 72 individuals with high (HIGH group) and 47 individuals with low (LOW group) hypnotic susceptibilities to undertake tests of NEO-PI-R and the Stanford Hypnotic Susceptibility Scale, Form C (SHSSC).

RESULTS

The HIGH group scored significantly higher than the LOW group did on openness to experience and its facet openness to feelings. In the LOW group, SHSSC total was positively predicted by openness to ideas; age regression was positively predicted by openness to experience and negatively predicted by extraversion; anosmia to ammonia was negatively predicted by agreeableness; and negative visual hallucination was positively predicted by openness to experience. In the HIGH group, hallucinated voice was positively predicted by openness to experience and negatively predicted by agreeableness, and posthypnotic amnesia was positively predicted by extraversion and negatively predicted by openness to experience.

CONCLUSION

The associations between normal personality traits and hypnotic susceptibility items were weak and different in the two groups, which imply that managing mental or somatoform disorders might be through adjusting hypnotizability and mobilizing personality functions.

Chaos-chaos transition of left hemisphere EEGs during standard tasks of Waterloo-Stanford Group Scale of hypnotic susceptibility

A recent study, recurrence quantification analysis of EEG signals during standard tasks of Waterloo-Stanford Group Scale of hypnotic susceptibility investigated recurrence quantifiers (RQs) of hypnotic electroencephalograph (EEG) signals recorded after hypnotic induction while subjects were doing standard tasks of Waterloo-Stanford Group Scale (WSGS) of hypnotic susceptibility to distinguish subjects of different hypnotizability levels. Following the same analysis, the current study determines the capability of different RQs to distinguish subjects of low, medium and high hypnotizability level and studies the influence of hypnotizability level on underlying dynamic of tasks. Besides, EEG channels were sorted according to the number of their RQs, which differed significantly among subjects of different hypnotizability levels. Another valuable result was determination of major brain regions in observing significant differences in various task types (ideomotors, hallucination, challenge and memory).

Preliminary study of relationships between hypnotic susceptibility and personality disorder functioning styles in healthy volunteers and personality disorder patients

BACKGROUND

Hypnotic susceptibility is one of the stable characteristics of individuals, but not closely related to the personality traits such as those measured by the five-factor model in the general population. Whether it is related to the personality disorder functioning styles remains unanswered.

METHODS

In 77 patients with personality disorders and 154 healthy volunteers, we administered the Stanford Hypnotic Susceptibility Scale: Form C (SHSSC) and the Parker Personality Measure (PERM) tests.

RESULTS

Patients with personality disorders showed higher passing rates on SHSSC Dream and Posthypnotic Amnesia items. No significant correlation was found in healthy volunteers. In the patients however, SHSSC Taste hallucination (β=0.26) and Anosmia to Ammonia (β=-0.23) were significantly correlated with the PERM Borderline style; SHSSC Posthypnotic Amnesia was correlated with the PERM Schizoid style (β=0.25) but negatively the PERM Narcissistic style (β=-0.23).

CONCLUSIONS

Our results provide limited evidence that could help to understand the abnormal cognitions in personality disorders, such as their hallucination and memory distortions.